The present invention relates to firefighter and other hazardous duty garments, and more particularly, reflective trim for use with such garments.
Reflective trim material is used on the outer shells of hazardous duty garments such as firefighter garments, as well as on jogging suits and construction worker garments, to make the wearers of such garments more visible to others in low visibility areas or in vehicle headlights in dark or low-light environments. Thus, reflective trim material provides an advantageous safety factor for the wearers of such garments.
Firefighter garments present special problems to a wearer. Unlike other types of garments, firefighter garments are to be worn in extremely hazardous environments, and must be designed to withstand temperatures in excess of 500.degree. F. without significant degradation. A firefighter garment typically is comprised of an outer shell of an aramid fiber such as NOMEX (a trademark of E.I. Dupont de Nemours & Co.), a moisture barrier comprised of a semi-permeable membrane bonded or otherwise attached to a substrate of an aramid fiber, and a thermal liner, which typically consists of a batting of aramid fibers. While such an ensemble will withstand the necessary heat and moisture (which tends to reduce the heat resistant capacity of a firefighter garment if the thermal barrier becomes soaked with moisture) a significant problem has arisen with respect to the stress imposed on a wearer resulting from trapping heat within such firefighter garments.
Since the human body eliminates heat primarily through the mechanism of the evaporation of liquid perspiration, any clothing which restricts or inhibits the transport of perspiration moisture vapor will cause a build-up of perspiration--and hence heat--within the coat, resulting in added stress to the wearer. Consequently, it is important to maximize the flow of perspiration moisture vapor outwardly from the wearer through the aforementioned components of the firefighter ensemble.
Conventional reflective trim material is applied to the outer shell of a firefighter garment and is a continuous non-permeable, non-perforated sheet of material. A problem with such reflective trim material is that it does not easily permit the transfer of perspiration moisture vapor. Accordingly, use of such reflective trim material on the outershell restricts the rate that moisture vapor permeates through the outershell of the garment. Consequently, areas of the firefighter garment under the reflective trim material retain an undesirable amount of water, if such moisture vapor condenses. Such excess water retained by the firefighter garment may impose added weight, block further moisture vapor transfer, and/or transfer external heat to the wearer.
Accordingly, there is a need to facilitate moisture vapor transport through the outer layers of the garment, especially through portions of the outer layer covered by reflective trim material.
Attempts have been made to enhance water vapor transport from a wearer of a garment through the garment and reflective trim to the external environment. One such attempt is illustrated in the 1997 edition of N.F.P.A. 1971, which is incorporated by reference herein. In particular, paragraph 4-1.14.5 of the N.F.P.A. 1971 calls for staggering the reflective trim on the sleeves of firefighter garments (see N.F.P.A. 1971 (1997) FIG. 4-1.14.5 options 2 and 4). However, the staggered trim configuration makes it difficult for wearers of the garment to flex their elbows.
Another attempt at making breathable reflective trim material is disclosed in U.S. Pat. No. 5,207,852 to Lightle et al. That patent discloses a flexible, air-permneable retroreflective sheeting for clothing having retroreflective elements partially embedded on one side of the fabric. Microspheres having reflective layers provide the reflectivity characteristic of the material. The reflective sheeting employs an air-permeable web which facilitates the transport of air into and out of the garment. Accordingly, the permeability of this reflective sheeting is an inherent characteristic of the air-permeable web employed in the sheeting. No perforations are incorporated into the reflective sheeting. The manufacture of such retroreflective sheeting is reasonably costly due to the various components needed to be combined to make such sheeting.
Accordingly, there is a need for a breathable reflective trim material for use with garments, especially firefighter garments, which can enhance the transport of vapor such as water or moisture vapor from a wearer of the garment to the external environment; and there is a need for a breathable reflective trim suitable for use with firefighter garments which can be cost effectively and efficiently manufactured.